Plant for the fabrication of parallel molded construction elements

ABSTRACT

A plant for the molding of heavy prefabricated construction elements. A plurality of form panels arranged between a fixed end wall and a mobile end wall are supported on pairs of rails and serially connected together by cables. The mobile end wall is provided with drive means for displacing it as well as the form panels between an open and closed position. The form panels are provided with vibrator devices and heating conduits. Damping means are arranged between the panels and the frame for reducing the transmission of vibrations from the panels to the frame. A latching assembling including pivoting hooks cooperating with pins on adjacent panels and connected by cables to the pivoting hooks of adjacent panels enables the panels to be coupled and uncoupled automatically one after another in response to the displacement of the mobile end wall. Tie-rods in cooperation with hydraulic cylinder and piston units enable the tightening of cavities formed by pairs of adjacent form panels. Adjustable movable flanges on one of the faces of each of the form panels define the side edges of the construction elements in cooperation with the other faces of adjacent form panels.

United States Patent [191 Fougea May6, 1975 [75] Inventor: Edouard Maire Fougea, Paris,

France [73] Assignee: Constructions Edmond Coignet, Paris, France [22] Filed: Nov. 27, 1972 [21] Appl. No.: 309,815

[30] Foreign Application Priority Data Dec. 6, 1971 France 71.43664 [52] US. Cl. 425/432; 249/81; 249/120; 249/129; 249/158; 425/441 [51] Int. Cl B28b l/08 [58] Field of Search 249/79, 81, 119, 120, 129, 249/l60168, 158, 169, 121; 425/182, 432, 436, 441, 450, 456; 122/511; 235/48-49,

1/1968 Netherlands 285/48 11/1970 United Kingdom 249/119 Primary Examiner-Robert D. Baldwin Assistant Examiner-John McQuade Attorney, Agent, or FirmDiller, Brown, Ramik & Wight [57] ABSTRACT A plant for the molding of heavy prefabricated construction elements. A plurality of form panels arranged between a fixed end wall and a mobile end wall are supported on pairs of rails and serially connected together by cables. The mobile end wall is provided with drive means for displacing it as well as the form panels between an open and closed position. The form panels are provided with vibrator devices and heating conduits. Damping means are arranged between the panels and the frame for reducing the transmission of vibrations from the panels to the frame. A latching assembling including pivoting hooks cooperating with pins on adjacent panels and connected by cables to the pivoting hooks of adjacent panels enables the panels to be coupled and uncoupled automatically one after another in response to the displacement of the mobile end wall. Tie-rods in cooperation with hydraulic cylinder and piston units enable the tightening of cavities formed by pairs of adjacent form panels. Adjustable movable flanges on one of the faces of each of the form panels define the side edges of the construction elements in cooperation with the other faces of adjacent form panels.

11 Claims, 16 Drawing Figures PATENIEDMAY slurs 3,881,856

SHEEI 1 [IF 6 PATENTEU MAY 6 I975 SHEET 2 BF 6 PATENIEBMAY 8I975 3,881,856

sum 3 0F 6 PATENIEDMAY 6l975 SHEET HUF 6 PATENIEDMAY 61975 0 H LP I I I HHI IH IHHH 0 1 fl l a l l l l l UH Hl l l l i l SHEET 5 0F 5 nHl Hl l lH Ul l l l lHHHI I IH I IHHHIH PHUU FIG. 70

PATENIED m e 1915 SHEET 8 OF 6 Q wt 8 m E PLANT FOR THE FABRICATION OF PARALLEL MOLDED CONSTRUCTION ELEMENTS BACKGROUND OF THE INVENTION The present invention concerns a plant for the fabrication of molded construction elements, in particular heavy prefabricated molded construction elements.

Plants are known which comprise a bay of vertical form panels arranged on a support and adapted to be positioned relatively close together for forming molding cavities and relatively far apart for enabling the removal of formed construction elements.

The form panels are adapted to be supported at their lower ends track and held tightly together during the molding.

According to another known technique the form panels are not supported at their lower ends on track but, on the contrary, are suspended from a rail carried by a frame along which they may be displaced for opening or closing the bay.

Such plants known at the present are not entirely satisfactory owing to the fact that the operation of each bay of form panels requires a substantial labor force.

Besides a substantial increase in the cost price of such construction elements, serious accidents may occur during the operation of a bay owing to the equipment in use.

Another disadvantage is that the resulting construction elements form plants currently in use do not have the desired surface finish and the dimensional tolerances and therefore require subsequent finishing or machining.

SUMMARY OF THE INVENTION An object of the present invention is to overcome the disadvantages set forth above, and to this end consists in a plant which in addition to its simple construction enables a rational, continuous production of prefabricated construction elements under excellent safety conditions and very profitably.

A more particular object of the invention consists in a plant for the molding of construction elements of this type comprises a frame, a plurality of form panels defining molding cavities and supported on the frame, said form panels having a relatively close-together position for the molding of the construction elements and a relatively spaced-apart position for removing the molded construction elements from the bay, said form panels being disposed between a stationary end wall associated with said frame, and a mobile end wall which is controlled for displacement to bring together and move apart said form panels for enabling the molding of construction elements and their removal from the bay.

Another particular object of the invention consists in a plant for molding construction elements, comprising a frame, a stationary end wall, a mobile end wall, a plurality of form panels suspended from the frame between said end walls for forming a plurality of molding cavities, said form panels having a close-together position for pouring concrete into said cavities and a spaced-apart position for removing the formed construction elements from said cavities, the mobile end wall being provided with driving means for displacing the form panels between their close-together and spaced-apart positions, a latching assembly for main taining the form panels in their close-together position during molding of the construction elements comprising a coupling member pivoted on each form panel adapted to engage a complementary associated member on an immediately adjacent form panel, and cables connecting adjacent coupling members so that upon moving the mobile end wall in a first direction to open the molding cavities, the cables are tensioned one after another to pivot the coupling members in succession out of engagement with their associated complementary members, and upon moving the mobile end wall in the opposite direction to close the molding cavities, the cables are relaxed one after another to allow the coupling members to pivot in succession into engagement with their associated complementary members under the force of gravity.

The molding cavities are constituted in a known manner of lower and side flanges and possibly upper flanges associated with one of the form panels while the immediately adjacent form panels is provided with a flat surface for cooperation with the flanges which are preferably adjustable.

According to a particular feature of the invention, the side flanges are slidably mounted on the lower flange and joined to a rotary operating shaft whose axis extends along one side of the form panels and comprises, in addition, locking means adapted to cooperate with the faces of two adjacent form panels.

The operating shafts are preferably controlled simultaneously and automatically by mechanical means such as hydraulic piston and cylinder units or a system of rods. or independently by a workman.

According to an other feature of the invention the form panels are connected together by lateral cables serially connected such that the displacement of the mobile end wall which may be provided with driving means or driven by independent control means assuring the opening of the form panels one after another as well as their closing.

According to further features, the form panels or shutterings are provided with vibrator devices installed in recesses, heating means mounted on the median longitudinal plane of the form panels, double roller means on damped bearing surface, and tightening means operative in the closed position of the bay.

Important advantages result from the preceding features.

A mechanism for the opening and closing of the bay having the following advantages:

1. quick opening and closing;

2. substitution of mechanical means for manual operations, a single workman being able to effect the opening or closing of a bay of molding cavities;

3. a system of coupling hooks enables the translatory movement of the form panels with their associated formed construction element without any risk of dropping the molded element;

4. a wide-open position of the bay with predetermined spacing between the form panels which makes possible the removal of molded construction elements and the preparation of the molding cavities for re-use.

In the close-together position of the form panels they are very tightly held together to withstand opposed forces exerted during the pouring of concrete. The form panels are tightly held together by double tie-rods of thin section which are therefore light and easily maneuverable.

It should be noted with respect to the double tie-rods (three pairs at the bottom and two pairs at the top). they entirely free the upper regions of the cavities which greatly facilitates the filling of the cavities.

Further. the forces developed by the pressure of the poured concrete on the form panels are directly passed on to the tie-rods without transmitting forces to the frame.

Another advantage of the invention is the arrangement of vibrator devices in upper recesses which directly effects the vibration of the interior of the cavities as the filling of the molding cavities is effected. an integrated vibration of the freshly poured concrete is therefore obtained. Housed in recesses in the form panels, the vibrator devices are protected from possible shocks but remain easily accessible for maintenance.

Heating means disposed along the longitudinal axis of the form panels enables penetration at any point along the form panels for introducing accessories without damaging reinforcements.

Since the form panels are to some extent independant, supply means is associated with them allowing the connection and disconnection for communication with a steam supply pipe and a condensate return pipe without any manual operations.

With this set-up long Bowden wires which might interfere with the activities of a workman are eliminated.

Other features and advantages of the invention will more over be brought out in the description which follows by way of example.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevation view of the plant according to the invention;

FIG. 2 is an end view of the plant;

FIG. 3 is a top view of the plant;

FIG. 4 is a perspective view illustrating a form panel;

FIG. 5 is also a perspective view and partly shows the stationary end wall, the mobile end wall and a single intermediary form panel;

FIG. 5A shows a detail of a wheel supporting carriage;

FIG. 6 is a perspective view illustrating the control mechanism for adjusting the position of the side flanges;

FIG. 7 is a vertical cross section taken along the line VIIVII in FIG. 6;

FIG. 8 is a partial. schematic perspective view of an upper flange particularly for a vertical partition or wall element;

FIG. 9 shows in perspective a bay of form panels with heating means;

FIG. 10 is an elevation view in section showing the connection of a branch circuit with the central heating circuit;

FIG. 11 is a view in section taken along the line XIXI in FIG. 9;

FIGS. l2-l5 schematically illustrate the various operating positions of the bay.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the embodiment illustrated in the accompanying figures the plant for the molding of construction elements intended for heavy prefabrication comprises a frame 10, a bay of form panels 11 suspended from the frame and displaceable thereon by means of rollers or wheels along outer and inner rails 13 and 14.

A stationary end wall 16 supported on the frame 10 is located on one side of the form panels 11, and a mobile end wall 17 is displaceable along one of the rails 13 or 14. The stationary end wall 16 and each one of the form panels 11 (see FIGS. 4 and 6 in particular) are provided with lateral flanges 21 and 22 and lower flanges 20 on one of their faces 19. The lateral flanges 21, 22 are preferably displaceable by means which will be described hereinbelow, whereas the lower flange is preferably fixed in the present embodiment. The flanges 20-22 are adapted to cooperate with a flat face without flanges 24 of an adjacent form panel to form in their close-together position, molding cavities C which define the shape of the construction element to be formed.

The movable form panels 11 are suspended on rails on laterally extending overhanging portions or arms 26 and 27 (FIG. 5) of unequal length so that a first series of form panels is supported on the outer rails 13 for displacement thereon and a second series of form panels 11' alternating with the first series is supported on the inner rails 14 for displacement thereon.

As will easily be seen from FIGS. 5 and 5A, the rollers or wheels 12 are arranged in pairs on a carriage 28 fixed to the overhanging portions 26, 27 for the form panels 11. Each carriage comprises a roller support housing 29, an element 29A connected to the associated overhanging portions 26 or 27, and a slab or plate 30 of flexible material forming clamping means sandwiched between the roller support housing 29 and the connecting element 29A.

It should be noted that the center of each carriage 28 is set off relative to the median plane of its associated form panel in order to maintain the form panels 11 strictly vertical so that the resulting molded construction elements whose upper and lower sides are strictly perpendicular to the faces of the construction element.

Moreover, the displacement of form panels maintained vertically by their rolling assemblies enables the removal of tapered molded construction elements without disassembling the molding cavity formed by a pair of form panels.

Furthermore, the damping means of the carriages allows the vibration of the form panels only and thereby it eliminates the vibration of the axles of the rollers relative to the rails as well as the transmission of these vibrations to the frame or the ground.

The mobile end wall 17 is secured at its lateral sides to an immediately adjacent form panel and the form panels are likewise attached to one another at their lateral sides, the form panel immediately adjacent the stationary end wall 16 being attached thereto.

The connection between the mobile end wall 17 and the immediately adjacent form panel 11 (clearly shown in FIG. 5 and FIGS. 12l5) is a flexible cable 3] disposed on each lateral side. One end of the cable 31 is secured to the mobile end wall 17 and the other end is secured to the pivot pintle 32 of an L-shaped coupling hook 33 with legs of unequal length.

The pivot pintle 32 of the coupling hook 33 is located at the corner formed at the meeting of the legs 34 and 34A of the coupling hook. A notch 36 is provided at the free end of the coupling hook 34 to cooperate with a protruding pin 38 extending from the immediately adjacent form panel.

The flexible connections between the form panels comprising cables 31 disposed along the lateral faces of the form panels are attached at an end to a pivot pintle of the coupling hooks 33 and by their other end at the terminal portion of the shorter leg 34A of the coupling hook.

The form panel immediately adjacent the fixed end wall 16 is secured thereto by cables similar to the cables 31, one end of which secured to the fixed end wall and the other to the free end portion of the shorter leg of the coupling hook.

The serial connection is thus constituted and the operation thereof will be described in detail hereinbelow.

Above it was seen that the lateral flanges 21, 22 on the form panels and the stationary end wall were adjustable. To this end the flanges 21, 22 are each associated with a control mechanism which will now be described with reference in particular to FIG. 6. The control mechanism associated with each form panel is the same; therefore. only one of these will be described.

The lateral flange 21 is mounted by forked members 40, 41 above pivot pins 42, 43 on upper and lower rods 44, 45, each connected by pins 46 and 47 to pivot arms 48, 49 fixed for rotation with an operating shaft 50 which is supported by bearings 51, 52 on the lateral side of the associated form panel.

The end of the rods 44 and opposite the forked members 40. 41 are provided with forked members 55 comprising a series of holes 56 enabling the adjustment of the length of the rods and consequently the position of the associated lateral flanges.

Once the lateral flanges are correctly positioned according to the length of the construction element to be formed. it must be maintained in this position. With this in view. the operating shaft carries between two pivot arms 48 and 49 locking arms 60 with substantially right-angle elbows so as to form an extension 61 in the direction of the molding cavity.

The extension 61 (see FIG. 7 also) carries at its free end adjustment means comprising, for example. nut and bolt means 62. [t is also seen in FIG. 7 that the flat face of the immediately adjacent form panel is provided with a holding plate 63 mounted on spindles 64 fixed to the form panels and bearing against a stack of Belleville washers constituting a damper. The holding plate 63 is arranged to cooperate between the spindles 64 with the extension 61 of the looking arm 60.

It will be understood that once the form panels are moved together. the extension previously brought between the spindles is held thereby and prevents any rotation of the operating shaft 50 and consequently any displacement of the associated flange since the operating shaft is common to the locking arm and the rods. A similar control mechanism is provided on the other side of the form panel and on each of the other form panels as well as the stationary end wall.

In case that the construction elements are intended to be used as wall members or vertical partitions, they must have an edge of a suitable profile 70 (FIG. 8) which is made possible by the upper flange 71 being pivotally mounted about a pivot 72 on forked members 73 arranged at the upper end of the form panel.

The upper flanges are adapted to be moved to a raised position which enables the removal of the formed construction element from its molding cavity. and a lowered position in which the upper flanges are inserted between the lateral flanges and close off the molding cavity.

With a view toward molding construction elements, the form panels may be brought together and tightened by means of a device shown in FIG. 5 comprising receiving blocks integral with the stationary end wall and receiving blocks 81 integral with the mobile end wall. These blocks are constituted by projections on the upper and lower edges of the end wall. Preferably two projections or blocks are provided along the upper edge of the end wall and three such projections are provided along the lower edge thereof.

The receiving blocks 81 on the mobile end wall 17 project substantially in the plane of the form panels. The lateral sides of the blocks include slot 82, 83 inclined downwardly and adapted to receive a pair of tierods 84, 84A having stop collars 85 adapted to abut against the outer face 86 of the blocks 81 and the outer face 87 of a thrust plate 88 having similar slots 89, 90 for receiving the tie-rods. The thrust plate is secured to a piston rod 92 ofa hydraulic and piston unit 93 carried on the blocks 80 integral with the stationary end wall.

After the form panels are brought together to define molding cavities, the tightening of the form panels in the bay is simply carried out by the tie-rods 84, 84A which are temporarily held in place on the blocks by the inclined slots in the plate 88 and in the blocks 81. By the operation of the cylinder and piston units 95. the tie-rods are tensioned maintaining the form panels in the bay in the closed position.

Vibration is necessary during the pouring of fresh concrete. To this end, each of the form panels is preferably provided with a vibrator device 95 (FIG. 4) of any suitable type which is housed in a fluidtight recess 96 and disposed in the upper part of the form panel.

Exposed vibrator devices 92 are fixed at the lower edge of each of the form panels.

Three vibrator devices may be provided in the upper part and two in the lower part as illustrated in FIG. 4.

For heating the poured concrete in the molding cavities. a coil 99 comprising three units 99A, 99B. 99C is housed within each hollow form panel and supplied by a steam supply pipe circuit 100.. A condensate or return pipe circuit 101 is connected to the end of the steam supply circuit 100.

The inlets and outlets of circuit of each form panel are connected to main supply and return pipes 102 and 103. Holes 104 are disposed in the lower edge of each form panel to assure the circulation of air inside the hollow form panels. The coil 99 is supported on supports 105 comprising (see FIG. 11) a curved bearing element 106 at the top and a block 107 of plastic material at the lower end. i

The inlets and outlets and 101 project beyond the lower end of each form panel terminating in a T- coupling (FlG. 10). One arm of the cross bar of the T- coupling ends with an opened or cup-shaped coupling flange 110, the other arm of the cross bar comprising a metal bellows 111 and a flat coupling flange 112. A sealing member 113 is received inside the open flange coupling 110.

The projecting T-shaped portions of the coil assure the maintenance of the coil in a central position enabling expansion in both directions of the plane of the coil in order to avoid the damaging of the coil by successive expansion and contraction.

The sealing members 113 interposed between the flat coupling flanges 112 and the open coupling flanges 110 are steam and hot-water resistant. When the bay of molding cavities is closed, the flat pipe coupling flanges 112 are successively received in the open coupling flanges I10 thereby forming a fluidtight assembly with the aid of the metal bellows 111 under the action of the stationary and mobile end walls 16 and I7, and the tierods 84, 84A for tightening the bay of molding cavities. When the bay of molding cavities is opened, the supply and return pipes are automatically uncoupled.

The steam supply circuit of the stationary end wall is connected to a steam supply pipe as well as a condensate return pipe. Similarly, the return pipe of the stationary end wall is connected to a return pipe. The mobile end wall has only one pipe flange assembly.

The operation of such a plant may be as illustrated in FIGS. 12-15 in which the mobile end wall 17 comprises driving means M, and the frame 10 is provided with an abutment B defining the end of the path of movement.

In FIG. 12 the molding cavities C are formed by pairs ofjuxtaposed form panels P with flanges responsive to the translatory displacement of the mobile end wall 17 in the direction of the arrow F.

The coupling hooks 34 of each form panel are hooked at the ends of their long leg on the pins 38 of the immediately adjacent form panel thereby locking the bay of molding cavities by the tensioning of the tierods 84 under the action of the piston and cylinder unit 93.

In this position the concrete can be poured into the various molding cavities.

Once the concrete has been poured and sufficiently hardened, the formed construction elements may be removed. First, the force exerted by the cylinder and piston unit 93 is released thereby releasing the tie-rods which may then be removed manually.

After this step the driving means M for the mobile end wall is started by a workman in order to displace the mobile end wall in the direction of the arrow F1 (FIG. 13) pulling with it all the form panels during an initial period.

When the cable 31 connecting the last form panel with the stationary end wall 16 is tensioned, the pulling force exerted on the coupling hook 34 causes it to pivot out of engagement with the pin 38 on the next adjacent form panel thereby effecting the uncoupling of the associated form panel.

This process continues, the coupled pairs of form panels are uncoupled one at a time upon the tensioning of the cable and unhooking of the coupling hook until the mobile end wall 17 comes into contact with the abutment defining the end of the path B of travel at which point the forward movement is stopped and the motor is cut off (FIG 14).

In this position, that is the so-called open position of the bay of molding cavities. the removal of the formed construction elements may be effected by rotation of the operating shafts 50 acting against the lateral flanges.

After the faces of the form panels have been prepared for pouring a further series of construction elements, the driving means M is started and displaces the mobile end wall in the direction F2 in order to effect the closing of the bay of molding cavities (FIG. 15). During the translatory movement of the mobile end wall 17 it first comes into contact with the next adjacent form panel. The interconnecting cable 31 is thereby untensioned and the associated coupling hook 34 is free to fall under the force of gravity into coupling engagement with its associated pin 38. The mobile end wall 17 thus coupled to its next adjacent form panels drives this latter into coupling relationship with the form panels opposite thereto. This process continues until all of the molding cavities of the bay have been closed.

The tie-rods 84, 84A are then brought into operative condition and the bay of molding cavities is then in its so-called closed position ready to be filled with concrete for forming another series of construction ele ments.

The present invention is, of course, not limited to the preferred embodiment described and illustrated herein, but, on the contrary, includes all alternatives, modifications and equivalents in the scope of the appended claims. One such modification is the arrangement of more than one bay of molding cavities on a single frame. What I claim is:

l. A plant for molding construction elements comprising a frame, a plurality of form panels serially connected together, lateral and lower flanges provided on one face of each form panel for defining molding cavities with the other face of adjacent form panels, a stationary end wall fixed to the frame, and a mobile end wall displaceable along the frame for moving said plurality of form panels therewith, means permanently connected to the lateral flanges for displacement parallel to the associated form panel, the means for displacing the lateral flanges comprising a control mechanism including rods connected to the flanges and adjustably connected to pivot arms mounted for rotation on an operating shaft supported on one form panel of each pair forming a molding cavity, and locking means including locking arms rotatably mounted on the operating shaft and adapted to be held between the adjacent panels of each pair, vibrator devices mounted in fluidtight recesses in the form panels, and damping means arranged between the panels and the frame for reducing the transmission of vibrations from the panels to the frame.

2. A plant according to claim 1, wherein said flanges are disposed on one face of each form panel adapted to cooperate with a flat face of the immediately adjacent form panel with which it defines a molding cavity when the panels are in their close-together position.

3. A plant according to claim 1, wherein the locking arm has an end portion adapted to cooperate with at least one shock-absorbing plate carried on the face of the immediately adjacent form panel without flanges.

4. A plant according to claim 1, further comprising an upper flange pivotally mounted for enabling the removal of the formed construction element from its associated molding cavity, the inner surface of the flange having a configuration complementary to the desired edge profile of the construction element to be formed.

5. A plant according to claim 1, further comprising tie-rods for tightening the molding cavities in the closed position, and blocks provided along the upper and lower edges of the end walls in which said tie-rods are received.

6. A plant according to claim 5, further comprising a cylinder and piston unit fixed to the stationary end wall and connected to the tie-rods for their tensioning.

and outlets of the heating means of each form panel is T-shaped. one end of the cross bar of the T having a cup-shaped coupling flange and the other having a flat coupling flange, and resilient means interposed between a cup-shaped coupling flange and its associated flat coupling flange.

11. A plant according to claim 8, wherein three coils connected in parallel are provided in each form panel connected between a stream intake pipe and condensate return pipe. 

1. A plant for molding construction elements comprising a frame, a plurality of form panels serially connected together, lateral and lower flanges provided on one face of each form panel for defining molding cavities with the other face of adjacent form panels, a stationary end wall fixed to the frame, and a mobile end wall displaceable along the frame for moving said plurality of form panels therewith, means permanently connected to the lateral flanges for displacement parallel to the associated form panel, the means for displacing the lateral flanges comprising a control mechanism including rods connected to the flanges and adjustably connected to pivot arms mounted for rotation on an operating shaft supported on one form panel of each pair forming a molding cavity, and locking means including locking arms rotatably mounted on the operating shaft and adapted to be held between the adjacent panels of each pair, vibrator devices mounted in fluidtight recesses in the form panels, and damping means arranged between the panels and the frame for reducing the transmission of vibrations from the panels to the frame.
 2. A plant according to claim 1, wherein said flanges are disposed on one face of each form panel adapted to cooperate with a flat face of the immediately adjacent form panel with which it defines a molding cavity when the panels are in their close-together position.
 3. A plant according to claim 1, wherein the locking arm has an end portion adapted to cooperate with at least one shock-absorbing plate carried on the face of the immediately adjacent form panel without flanges.
 4. A plant according to claim 1, further comprising an upper flange pivotally mounted for enabling the removal of the formed construction element from its associated molding cavity, the inner surface of the flange having a configuration complementary to the desired edge profile of the construction element to be formed.
 5. A plant according to claim 1, further comprising tie-rods for tigHtening the molding cavities in the closed position, and blocks provided along the upper and lower edges of the end walls in which said tie-rods are received.
 6. A plant according to claim 5, further comprising a cylinder and piston unit fixed to the stationary end wall and connected to the tie-rods for their tensioning.
 7. A plant according to claim 1, wherein the vibrator devices are disposed in the upper portion of the form panels.
 8. A plant according to claim 1, further including heating means in each panel including coils connected in parallel.
 9. A plant according to claim 8, wherein each coil is provided with expansion means, and comprises an inlet and an outlet in communication with the coils of adjacent panels forming a heating fluid circulation circuit therewith.
 10. A plant according to claim 9, wherein the inlets and outlets of the heating means of each form panel is T-shaped, one end of the cross bar of the T having a cup-shaped coupling flange and the other having a flat coupling flange, and resilient means interposed between a cup-shaped coupling flange and its associated flat coupling flange.
 11. A plant according to claim 8, wherein three coils connected in parallel are provided in each form panel connected between a stream intake pipe and condensate return pipe. 